The government is conducting Small Business Sources Sought market research, not a solicitation, to assess qualified small business sources and determine the appropriate acquisition strategy for tau PET radiotracers for the Baltimore Longitudinal Study of Aging. The contractor would independently supply FDA-approved second-generation tau PET radioligand Lantheus [18F]MK-6240 for in vivo PET/CT scans measuring brain tau neuropathology in BLSA participants. The requirement is 70 tau radioligand doses in the base period and 70 doses in each of two option periods. Anticipated performance is Base Year November 18, 2026–November 17, 2027, Option Year 1 November 18, 2027–November 17, 2028, and Option Year 2 November 18, 2028–November 17, 2029. Interested respondents should demonstrate ability to meet the requirements and provide product literature or capability statements, business size/type, manufacturer or authorized distributor status, DUNS number, and contact information, with NIH particularly interested in small business sources.